The present invention relates to a sealing device comprising a sealing ring consisting of an elastic material and also comprising means for retaining the sealing ring in a groove in a pipe, especially during the mounting of the pipe joint.
In jointing different types of pipes and especially pipes consisting of plastic material and adapted to constitute water pipes which shall be able to stand substantial inner overpressures but also lower outer pressures, it is preferred to position the sealing rings for sealing the pipe joints in the grooves for retaining the sealing rings already at the manufacturing of the pipes. However, it has been difficult to provide for a secure retaining of the pre-mounted sealing rings during the transport and handling of the pipes with the sealing rings mounted therein. The problem or retaining the sealing rings during the jointing of the pipes is further emphasized in the case where the grooves have a bottom surface which is at least partly of a rounded shape. In this case, radially directed forces can create substantial twisting forces within the sealing rings which thereby may be placed in a position wherein they are not able to satisfy the intended sealing function.
As the type of pipe for which the sealing device according to the invention is especially intended are often used for outdoor water pipes, it has also been a problem to maintain the end portion of the pipe which is introduced into a sealing ring clean from dirt and foreign matter, especially as the mounting work must often take place outdoors under adverse conditions. This fact causes foreign matter to be introduced into the inner pipe and into the sealing ring, which causes leakage at the joint.